"As we closed out this budget, over the last two or three weeks in particular, a great deal of concern was being raised with current inventory levels, particularly given some of the expenditures in the CENTCOM area of operations," Roth said. "So the secretary mandated and insisted we fully fund, to the maximum extent possible, the full production capacities for certain selected preferred munitions."

7,312 Small Diameter Bombs (SDB), worth $504.1 million to Boeing and Raytheon

100 Tomahawk Missiles, worth $381.6 million for Raytheon

An unlisted number of Advanced Precision Kill Weapon Systems (APKWS), worth $200 million

All in all, the Pentagon is asking for about $16.4 billion in missiles and munitions in the 2018 fiscal year budget.

The DoD said it has spent about $2.8 billion on munitions since the August 2014 start of the campaign against ISIS up to the end of March 2017. And Air Force Maj. Gen. James Martin Jr. said on Tuesday that munitions reserves are "challenged" by the current operations.

In February, Trump requested an extra $54 billion in defense spending for 2018. The request has been criticized by lawmakers on both sides of the aisle as being too little, or cutting too much from domestic spending and foreign aid.